according to toyota specs, curb weight for the 4 door is 1,730 kg, so maybe 1,600 ish. ;-)
Tow capacity is about 700 kg, with 70 kg of tongue weight.
Considering our RAV's modest torque rating, and your non-limited slip AWD, I wouldn't expect HUGE inclines to work, but atleast 30 degrees, depending on the loading. Drive SLOW with your differential locked (if possible).
Do you have a manual transmission or auto?
(manual can handle more than 700kg without overheating/stressing, at your own risk)
Aftermarket springs and shocks?
(helps with extra weight sometimes)
Do you have the factory tow hitch or an aftermarket?
(1 1/2" vs 2" shank and Class I, II, or III)